Hot water heating system



Aus- 4, 1942 H. A. LocKHART ETAL HoT wATEE HEATING SYSTEM Filed March 18, 1940 3 Sheets-Sheet l All@ 4. 1942- H. A..LocKHART Erm. 2,292,138

HOT WATER HEATING SYSTEM Filed March '18, 1940 3 sheets-sheet 2 y Aw,

All@ 4, 1942- H. A. LocKHART ETAL 2,292,138

HOT WATER HEATING-SYSTEM Filed March 18, 1940 I5 Sheets-Sheet 3 'Patented Aug. 4,', 1942 ,Y

HOT WATER HEATING SYSTEM Harold A. Lockhart, Des Plaines, and Lawrence J.

Smith, Oak Park, Ill., assignors to Bell & Gossett Company, Chicago, Ill., a corporation of l1- linois Application March 18, 1940, Serial No.`324,478

11 Claims.

Our invention relates to closed hot water heathand fired, down-feed type in which the supply and return lines are located below the boiler, or the radiating devices are disposed below the supply and return lines.

Closed systems are customarily provided with an expansion tank which accommodates the expansion of the water when heated without losing water from the system and which is ordinarily mounted above the boiler and connected to the supply main issuing from the top of the boiler. A system of this type in which the mains are disposed below the boiler or the radiators vbelow the mains also employs a circulating pump, responsive to a room thermostat or an aquastat in the boiler acting as a high limit switch, because the water will not circulate thermogravitationally. Notwithstanding the positive circulation of the water and the accompanying dissipation of heat, excessive temperatures and pressures are occasionally built up in this type of system, due to lack of care in firing. It has been observed that undertheseV conditions the circulation of the water stops, although the pump may be operating, and that accordingly the boiler is placed under such a strain due to the overheating that it may be ruptured.

It is therefore the principal object of our invention to insure a forced circulation of the water through the system under all conditions of excessive or run-away firing.

These and further objects of our invention will be set forth in the following specification, reference being had to the accompanying drawings, and the novel means by which said objects are efl'ectuated will be definitely pointed out in the claims. I

Fig. 1 is a diagrammatic, perspective view of one form of our improved heating system in which the supply and return lines are disposed below the boiler.

Fig. 2 is a modification of the system shown in Fig. 1.

Fig. 3 is a further modification of the system shown in Fig. 1 and in which the supply and return "lines are disposed generally above the boiler with down-feed connections to the boilers.

Figs. 4 and 5 are modifications of the system illustrated in Fig. 3.

' ing systems and more particularly those of the l nected to the riser I2 and extends below the 55 floor I I for connection to any desired number of heating units, such as the usual radiator I4. A circulating pump l5 may be mounted in the supply line I3 and may be driven by a motor I6 whose operation is responsive to a room thermostat I1 that is exposed in the space where the radiators are situated, the thermostat and Lne motor being included in an electrical circuit designated generally by the numeral I8. The motor is also responsive to a reverse action aquastat I9 that is mounted in the boiler I0 and acts as a high limit, safety switch, the aquastat being wired in parallel with the room thermostat as designated generally by the numeral 20. The return line from the heating units is indicated by the numeral 2I and may enter the boiler I0 adjacent the lower portion thereof. This return line may also include the usual drain valve 22.

One end of a pipe 23 is connected to the riser I2 and the opposite end to the usual expansion tank 24 that may be disposed above the boiler and which is intended to accommodate the expansion of the water in the system when heated. If desired, a relief valve 25 may be connected to the riser 'I2 and the latter, above the connection of the pipe 23 thereto, may be provided with an air vent 26.

So far as described, the system is the customary, forced circulation, down-feed type of hot water heating arrangement in which the pump I5 acts to circulate Water through the system in response to the demand of the thermostat I 1 for heat, or to dissipate-heat throughthe system in response to the demand of the aquastat I9 Whenever the boiler water attains a predetermined, maximum temperature; regardless of whether the room thermostat is demanding heat at the same time.

It has been ascertained that under certain conditions of careless or run-away firing and notwithstanding the continued .operation of the circulating pump which endeavors to dissipate the heat through the system, a condition may be reached such that no water is circulated through the system, even though the pump may then be operating. Obviously, if this situation persists for an indefinite time, the boiler may be ruptured by the high pressure.

The exact reason for this phenomenon is not known, but we have ascertained that the fault can be corrected by connecting one end of a pipe 2l to the lower portion of the tank 24 and the opposite end to the return line 2 I. With this pipe installed, the pump I5 will always circulate water through the system regardless of continued and excessive firing.

In Fig. 2 the tank 34 is also disposed above the boiler and is connected to the upper portion thereof by a pipe 35 and to the riser 36 by a second pipe 31. Otherwise this lsystem is identical with that shown in Fig. 1.

In Fig. 3 there is illustrated a modification of the system shown in Fig. 1, the variation consisting in disposing the supply and return lines above the boiler with downfeed connections therefrom to the usual radiators. To this end the numeral 3B designates the boiler from which issues a riser pipe 39 that is connected to a supply line 40 disposed above the boiler and from which extend downfeed supply and return pipes 4l and 42, respectively, to a radiator 43. The supply line iinally connects with the return line 44 which may include the usual circulating pump 45 and the terminal end of the return line 44 is connected to the-lower portion of the boiler. In order to lighten the load on the pump and to facilitate flow through the radiators, the pipes 4i and 42 may be connected to the supply line by fittings of the type disclosed in Patent No. 1,663,271.

Asin the preceding types of systems an expansion tank 46 is disposed above the boiler and has its lower portion connected to the riser 39 by a pipe 41 and a second pipe 48 also connects the lower portion of the tank 4,6 with the return line line 44. Otherwise the system is identical with that illustrated in Fig. 1 including the electrical circuits for controlling the operation of the pump and the aquastat (not shown).

l The system shown in Fig. 4 is similar to that illustrated in Fig. 2 in that a pipe 55 corresponding to the pipe 35 in Fig. 2 connects the lower portion of the tank 56 directly with the upper portion of the boiler 51. The other pipe connection 58 leading to the lower portion olf the tank 56 is in communication with theusual riser In Fig. 5 the tank 66 is connected by a short pipe 6l to the usual riser 62 and also by a pipe 63 to the'return line 64.

Any of the modifications illustrated in Figs. l to 5, inclusive, are effective to insure a forced circulation of the water through the system at all times, regardless of any condition of excessive or run-away ring.

For purpose of illustration, each of the modications incorporates the so-called one pipe system, but it will be understood that the two pipe system in which the radiators are bridged between the supply and return pipes is regarded as being the full equivalent. In each case, a flow circuit leads from and returns to the boiler.

We claim: l

1. A closed hot water heating system ot the downfeed, forced circulation type comprising in combination, a boiler, supply and return lines connected to the boiler to form a main heatingI system with a portion of each line disposed below the upper part of the water space of the boiler, an expansion tank connected to the supply line, anda separate pipe connecting the lower portion of the tank with the return line.

2. A closed hot water heating system of the and a second pipe connecting the lower portion of the tank with the return line.

3. A closed lhot water heating system of the downfeed, forced circulation type comprising in combination, a boiler, supply and return lines connected to the top and bottom of the boiler, respectively, to form a-main heating system With a portion of each line disposed below the upper part of the water space of the boiler, an expansion tank, a first pipe connecting the expansion tank to the supply line, and a second pipe connecting the lower portion of the tank with the return line.

4. A closed hot water heating system of the downfeed, forced circulation type comprising in combination, a boiler, supply and return lines connected to the top and bottom of the boiler, respectively, to form a main heating system with a portion of each line disposed below the upper part of the water space of the boiler, an expansion 'tank located above the boiler, a iirst pipe connecting the tank to the supply `line and a second pipe connecting the lower portion of the tank with the return line.

5. A closed hot water heating system of the downfeed, forced circulation type comprising in combination, a boiler, a continuous pipe external of the boiler and having its inlet and discharge ends connected, respectively, to the upper and lower parts of the boiler, a radiating unit connected to the pipe, the unit and pipe being so related to the boiler that hot water moving to the unit is characterized by a downfeed flow, a closed expansion tank connectedto the pipe, and a separate pipe connecting the lower portion of the tank with the first-named pipe adjacent its connection to the lower part of the boiler.

-6. A closed hot water heating system having a downfeed, forced circulation type comprising in pump for circulating water therethrough comprising in combination, a boiler, and a pair of flow circuits connected in parallel relation to the boiler, a radiating unit being connected to `hot watermoving to the unit, is characterized by a downfeed iiow.

7. A closed hot water heating system having a pump for circulating water therethrough comprising in combination, a boiler, and a pair of flow circuits connected in parallel relation to the boiler, a radiating unit being connected to one of the circuits and the other circuit including a closed expansion tank located above the boiler, the unit and its connected circuit being so related to the boiler that hot water moving to the unit is characterized by a downfeed flow.

8. A closed hot water heating system oi' the forced circulation type comprising in combination, a boiler, a ilow circuit leading from and returning to the boiler to form a main heating system, a radiating unit connected to the circuit, the unit and circuit being so related to the boiler that hot water moving to the unit is characterized by a downfeed liow, a closed expansion tank communicating with the boiler, and a separate pipe connecting'the boiler to the lowenportion of the tank.

9. A closed hot water heating system of the forced circulation type comprising in combination, a boiler, a flow circuit leading from and returning to the boiler to form a main heating system, a radiating unit connected to the circuit, the unit and circuit being, so related to the bOleI: that hot water moving to the unit is characterized by a downteed ilow, a closed expansion tank located above the boiler, a first pipe providing means of communication between the tank and boiler, and a second pipe connecting the lower portion oi the tank with the circuit.

10. A closed hot water heating system of the forced circulation type comprising in combination, a boiler, a flow circuit leading from the top and returning to the bottom of the boiler to form a main heating system, a radiating unit connected to the circuit, the unit andcircuit being so related to the boiler that hot water moving to the unit is characterized by a downfeed iiow, a closed expansion tank, a first pipe providing means of communication between the tank and boiler, and a second pipe connecting the lower portion of the tank to the circuit.

11. A closed hot water heating system of the downIeed forced circulation type comprising in combination, a boiler, a iiow circuit leading from and returning to the boiler to form a main heating system with a portion of the circuit disposed below the upper part of the water space of the boiler, a closed expansion tank communicating with the boiler, and a separate pipe connecting the lower portion of the tank to the circuit.

HAROLD A. LOCKHART. LAWRENCE J. SMITH. 

